Backtesting Your Trading Strategy

Backtesting allows you to validate your trading strategy using historical data before risking real capital. Every serious trader must backtest.

What is Backtesting?

Backtesting is the process of applying your trading rules to historical price data to see how the strategy would have performed in the past.

Why Backtest?

Validates (or invalidates) your strategy
Builds confidence in your approach
Reveals flaws before losing real money
Provides statistical data on expected performance
Removes emotional bias from strategy evaluation

Manual Backtesting Process

Step 1: Define Your Rules

Write out exact entry and exit rules:

Entry criteria (indicators, patterns, levels)
Stop loss placement
Take profit levels
Position sizing rules
Maximum trades per day/week

Step 2: Scroll Back in Time

Open your chart on the trading timeframe
Scroll back 6-12 months
Use the replay/scroll function to move forward candle by candle
Do NOT look ahead at future candles

Step 3: Record Every Trade

For each setup that meets your rules:

Entry date and price
Stop loss level
Take profit level(s)
Result: win, loss, or breakeven
Risk-to-reward achieved

Step 4: Analyze Results

After 100+ trades, calculate:

Win Rate: Percentage of winning trades
Average Win: Average profit on winners
Average Loss: Average loss on losers
Profit Factor: Gross profit / Gross loss
Maximum Drawdown: Largest peak-to-trough decline
Expectancy: (Win% x Avg Win) - (Loss% x Avg Loss)

What Good Results Look Like

Minimum Viable Strategy

Win rate: 40%+ with 1:2+ R:R, or 55%+ with 1:1 R:R
Profit factor: Above 1.5
Maximum drawdown: Under 20%
Expectancy: Positive number
Sample size: At least 100 trades

Backtesting Pitfalls

Curve Fitting

Optimizing for past data too much
Strategy works perfectly on history but fails live
Solution: Test on out-of-sample data

Survivorship Bias

Only testing on assets that still exist
May ignore delisted or failed assets

Look-Ahead Bias

Unconsciously seeing future data
Knowing the outcome before taking the trade
Solution: Use bar-by-bar replay

Ignoring Costs

Not accounting for spreads
Forgetting commissions
Ignoring slippage
These reduce profitability significantly

Forward Testing (Paper Trading)

After backtesting:

Trade the strategy live on a demo account
Minimum 1-3 months of forward testing
Compare results to backtest expectations
If results match: Go live with small size
If results differ: Investigate why

Key Takeaways

Never trade a strategy you have not backtested
Need 100+ trades for statistical significance
Beware of curve fitting and look-ahead bias
Forward test before going live
Backtesting builds the confidence you need